Rotary ribbon shuttle

ABSTRACT

AN INK TRANSFER RIBBON ADVANCING MECHANISM FOR A HIGH SPEED ROTARY PRINTING PRESS INCLUDING A PAIR OF ECCENTRIC ROLLERS ONE ON EACH SIDE OF THE ROLLING BIGHT OF THE PRESS IN FRICTIONAL CONTACT WITH THE RIBBON FOR ALTERNATELY ACCELERATING AND DECELERATING THE VELOCITY OF THE RIBBON THROUGH THE BIGHT.

Sept. 21, 1971 R.-COLW|LL v 6 3,606,836

ROTARY mason SHUTTLE Filed April 5, 1969 2 Sheets-Sheet 1 INVENT OR RICHARD COLWILL ATTORNEY p 1 1971 R. COLWILL ROTARY RIBBON SHUTTLE 2 Sheets-Sheet I Filed A ril 5. 1969 INVENTOR RICHARD COLWILL ATTORNEY United States Patent 3,606,836 ROTARY RIBBON SHU'ITLE Richard Colwill, Victor, N.Y., assignor to Burroughs Corporation, Detroit, Mich. Filed Apr. 3, 1969, Ser. No. 813,101 Int. Cl. B41t 31/00 US. Cl. 101244 7 Claims ABSTRACT OF THE DISCLOSURE An ink transfer ribbon advancing mechanism for a high speed rotary printing press including a pair of eccentric rollers one on each side of the rolling bight of the press in frictional contact with the ribbon for alternately accelerating and decelerating the velocity of the ribbon through the bight.

BACKGROUND OF THE INVENTION The art of printing characters impregnated with magnetic material on documents has been developed to satisfy the need for the ability to recognize characters by mechanical means as well as through the visual sense. The process is generally referred to as Magnetic Ink Character Recognition (MICR) and finds significant use in encoding checks and bank documents with bank transit numbers, account numbers, amounts, serial transit numbers, etc. The introduction of this process into the business document printing field has been instrumental in the successful implementation of rapid mechanical processing of bank documents.

Serial printers of rotary and non-rotary design have been employed to print successive forms with recent use found in printing MICR impregnated documents. In particular, high-speed rotary printing techniques have found common usage wherein a web or roll medium is imprinted by action of rotary members consisting of an anvil roll against which is successively pressed, a plurality of numbering machines mounted in the periphery of a drum. High-speed operation is achieved by continuous motion of the rotary members thereby imprinting without interruption of the continuously fed paper web or roll.

The numbering machines may be used in any desirable number and as such are drum mounted so that they present a set of characters that extend beyond the face of the drum. As the drum is rotated, each numbering machine is brought into squeezing contact with the anvil roll thereby constituting a printing bight. A print medium receives character impregnation as it is acted upon by a transfer ribbon engaged by the numbering machines in the bight. After each impregnation, another numbering machine rotates into printing contact with a progressive portion of the print medium and prints a progressive or repetitive alpha-numeric code upon the medium. However, giving the rotating members continuous motion is not enough to perform a satisfactory printing cycle. When the print medium and ribbon are acted upon by the rotating members in the printing bight, it is necessary that the motion of the members be synchronized to prevent smearing of the characters, uneven deposit of magnetic material and tearing of the medium or ribbon. Maintenance of character quality is a desirable result in all printing operations but especially important in documents subject to use in MICR systems requiring clearly defined characters in order to discriminate accurately among them.

Previous approaches toward solving the problems of smeared characters and torn paper and ribbon have featured synchronizing the rotary members and then passing 3,605,836 Patented Sept. 21, 1971 ice the print medium and transfer ribbon through the bight in a continuous manner so that all elements are traveling at zero relative velocity. However, such constant feed methods produced large quantities of unused ribbon. In practice, as each imprint is made about A lineal inch of ribbon is used. Since, when constant feed rolls are used, the ribbon is moving at the same speed as the rotating drum whereon the numbering machines are mounted, the ribbon advances several inches or approximately the circumferential distance between numbering machines before the next imprint is made and the next A lineal inch of ribbon is used. To economize on ribbon, intermittent feed reels have been used with the resulting necessity for either mechanical or electromechanical sensing devices that reveal the period during which ribbon feed is required for printing, with a means for accelerating the ribbon during this period. Another solution is shown by my U.S. Pat. No. 3,405,637 wherein a trapeze frame shuttles the ribbon through the bight thereby accelerating it at the time of printing contact. This invention reduced the quantity of ribbon used by momentarily imparting an acceleration to the transfer ribbon at the time of printing couple. At the non-printing time the forward motion of the ribbon is substantially reduced. Further simplicity was derived in Pat. No. 3,405,637 from the ability to use a constant rate feed and take-up spool to supply the ribbon to the shuttle since the only change in relative velocity of the ribbon occurs within the bounds of the shuttle. However, this apparatus produces noise and vibration that commonly accompany a mechanically activated frame.

OBJECTS OF THE INVENTION Accordingly, a principal object of this invention is to provide a simplified apparatus for continuously shuttling a transfer ribbon through a rotary printing bight, that substantially utilizes all of the area of the ribbon.

Another object is to provide a vibration and noise free apparatus which is used to shuttle a transfer ribbon through a rotary printing bight so that only the approximate amount of ribbon used in the printing contact is advanced through the bight.

SUMMARY OF THE INVENTION The invention comprises a pair of like eccentric rollers or cams, one on each side of a printing bight, oriented for complementary action and cooperating through frictional contact with the ribbon to accelerate and decelerate a transfer ribbon through the bight in an undulating manner. The eccentric rollers rotate in opposite directions and are coordinated with the rotary printing bight to accelerate the ribbon so that at the time printing couple occurs on the print medium, the ribbon has achieved velocity equal to that of the other members of the printing bight. During non-printing time, the eccentric rollers decelerate the ribbon, thereby substantially conserving the amount of ribbon passing through the bight. Ribbon is fed to and received from the eccentric rollers at a constant rate by variable speed feed and take-up spools which are metered and regulated to compensate for diminishing or increasing ribbon accumulation thereon. A constant rate of ribbon feed can be maintained in as much as the acceleration imparted to the ribbon carried between the eccentric rollers is solely contained therebetween and is achieved by the complementary camming surface of the eccentric rollers acting upon the ribbon.

DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic end view of applicants rotary ribbon shuttle showing the relationship of the operative 3 parts in an embodiment of the apparatus employing single lobe cams.

FIG. 2 is a modification of the apparatus as shown in FIG. 1 utilizing double lobe cams.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a rotary ribbon printing press utilizes a transfer ribbon 11 from which a printing substance, such as magnetic ink, is transferred to a print medium 13 in the form of a continuously moving web or roll. A rotating printing drum 15, squeezes the transfer ribbon 11 and the print medium 13 against the anvil roll 19 to form a printing bight. The printing drum 15 may be any known printing drum including one with characters dispersed about its circumferential area or one utilizing numbering machines mounted around its periphery. The preferred embodiment envisions the use of a plurality of numbering machines 17 displaced equidistance about the circumference of the printing drum 15, arranged in appropriate number and spacing to correspond to the progressive printing area presented by the print medium 13 as it advances through the printing bight.

The printing drum 15 and the anvil roll 19 rotate so that their circumferences travel in rolling cooperation and at the same velocity in a constant smooth motion. The transfer ribbon 11 and print medium 13 travel through the line of tangency of the circumferences of the printing drum 15 and anvil roll 19. The velocity of the print medium 13 is matched to that of the printing drum 15 and anvil roll 19 and feeds between them at a smooth and constant rate. However, the velocity of the transfer ribbon 11 through the bight varies, reaching its maximum of a velocity equal to that of the drum 15, roll 19, and print medium 13, at the time of printing contact then decreasing to substantially lower velocity during nonprinting time. This fluctuation in velocity is accomplished by the concerted action of the eccentric rollers or cams 21 and 23 upon the transfer ribbon 11.

Single lobe cams 21 and 23 are positioned prior to and after the printing bight. Essentially the cams 21 and 23 are tear-drop shaped with their axis of rotation located in the broader end of the cam. Each of their lobes is the apex of the tear-drop and it is described by the periphery at the greatest distance from the center of rotation. Both cams 21 and 23 operate at the same rate of axial rotation with their lobes cooperating by complementary action to reciprocate the ribbon 11 through the printing bight.

In the preferred embodiment, the cams 21 and 23 are of single lobe tear drop configuration, as described above. Preferably, the cams 21 and 23 rotate in opposite directions and are positioned on their shafts 22 and 24 so that the lobes are pointed in the same direction when parallel with, and in opposite direction when perpendicular to, the portion of the transfer ribbon 11 between the cams 21 and 23 and in the bight.

It is apparent, however, that the desired reciprocating action of the ribbon 11 can be achieved by eccentric rollers 21 and 23 of circular circumference having their axes of rotation off the center of the circle. In such an embodiment the major side of the eccentric would act the same as the lobe of the preferred embodiment.

The surfaces of the eccentric rollers 21 and 23 in contact with the ribbon 11 are smooth enough to allow the ribbon 11 to slide over the surface during part of this rotation and to drive the ribbon 11 during another part, as explained more fully hereinafter.

The transfer ribbon 11 is disposed around and in contact with the cams 21 and 23. It receives its animation from the rotation of the cams 21 and 23 and moves in an undulating motion through the printing bight. The effect of the coordinated action of the cams 21 and 23 on the transfer ribbon 11, is to impart an acceleration followed by a rapid deceleration and a relatively long period of retarded ribbon advance. The action of acceleration is 4 coordinated so that it occurs in time to accelerate the velocity of the transfer ribbon 11 to the velocity of the anvil roll 19, printing drum 15 and print medium 13 at the instant of printing.

The distinctive motion given to the transfer ribbon 11 may be best understood if its progress is followed around and between the cams 21 and 23. As the lobe of the cam 23 rotates counterclockwise through it acts with its relatively larger radius, on the portion of the transfer ribbon 11 extended between it and the cam 21. Concurrently, the ribbon 11 is sliding over the smaller radius of cam 21 thereby releasing the amount of lineal ribbon 11 previously acted upon by the larger radius of cam 21 and now required by the larger radius of the cam 23. The complementary give and take of the cams 21 and 23 allows a constant length of ribbon 11 to be disposed around and between the cams 21 and 23.

As the lobe of cam 23 continues to rotate counterclockwise through 180, the ribbon 11 slides over cam 235 smaller radius thus releasing the amount of lineal ribbon 11 required by the larger radius of cam 21 which has rotated 180 clockwise to operate on the ribbon 11 with its larger radius. The lobe of the cam 23 occupies a relatively small amount of the circumference. As cam 23 rotates, its lobe contacts transfer ribbon 11 for a brief period and acts with its larger radius to impart an acceleration to the velocity of the length of ribbon 11 between it and the cam 21. This impulse is timed so that it coincides with the moment of printing contact.

Mechanisms for driving shafts 22 and 24in synchronization and for adjusting the speed of one shaft with respect to another having long been known. The relative sizes of the radius of the cams 2 1 and 23 and relative velocity of the cams 21 and 23 with respect to the rotational velocity of the print drum 15 and the anvil roll 19 can easily be adjusted by one skilled in the art to gain maximum efiiciency in utilization of the transfer ribbon 11.

The transfer ribbon 11 is supplied to the cam 21 at a constant rate by the feed spool 25. The spool 25 operates at a variable speed to maintain a constant rate of ribbon feed as the quantity of ribbon 11 on said spool 25 decreases, as is known in the art. Metering roll 27 rests against the spool 25 and senses the quantity of ribbon 11 on the spool 25 and supplies a signal, by suitable known means, to the drive mechanism of the spool 25 to adjust its rate of rotation. The roll 29 acts on the spool 25 to tighten and secure the ribbon 11 on said spool 25, thereby preventing slack and spillage.

The take-up spool 31 performs the opposite function of the feed spool 25. It too has a metering roll 33 that adjusts its speed, as known, to provide a smooth decreasing rate of rotation, as the amount of ribbon 11 on the spool 31 increases, thereby receiving the transfer ribbon 11 from the cam 23 at a uniform rate. The roll 35 acts to tighten the ribbon 11 upon the spool 31 thereby preventing sli page and slack.

Arranged along the path of the transfer ribbon 11 are guide posts to position the ribbon 11 between the elements of the printing apparatus. The posts 37 and 39 act in unison between the spool 25 and the cam 21 to stabilize the position of the ribbon 11 as the cam 21 rotates and acts on the ribbon 11 with its unsymmetrical periphery. The posts 41 and 43 are interposed between the cams 21 and 23 to maintain the ribbon 11 in a stable plane as it passes through the printing bight. The posts 45 and 47 act in a similar fashion as the posts 37 and 39 to stabilize the ribbon 11 as it travels from the cam 23 to the spool 31.

This invention is envisioned for principal use in serial ribbon-printers featuring rotatably mounted numbering machines. When used in this type of a printer, single lobe cams 21 and 23 will be employed to impart matching velocity to a transfer ribbon 11 passing through. a printing bight composed of an. anvil roll 19 against which numbering machines 17 engage a print medium 13 and a transfer ribbon 11 in printing couple. Matched cams 21 and 23 are positioned on each side of the bight and will impart an undulating motion to a transfer ribbon 11 over its length tensioned between the cams 21 and 23. The ribbon 11 will be fed to and received from the cams 21 and 23 at a constant rate. The only variation in ribbon velocity will occur between the cams 21 and 23.

Where closer spacing between print regions on the continuous print medium 13 is required, the quantity of characters arranged around the printing drum 15 is increased to correspond. In this embodiment, printing contact occurs more frequently per revolution than where there is larger distance between print regions. Consequently, it is necessary to increase the number of times ribbon synchronization occurs to correspond to the increased printing contacts per revolution. Either the speed of the earns 21 and 23 may be proportionally increased or multiple lobe cams, running at the same or lower speed may be substituted to achieve the desired ribbon synchronization. Flexibility inheres from the ability to vary either separately, or in coordination, the number of lobes per cam and/ or its rate of revolution.

FIG. 2 shows an alternate embodiment in which the eccentric rollers are double lobed earns 49 and 51 mounted on shafts 48 and 52 replace the single lobed cams 21 and 23 respectively, the cams 49 and 51 being positioned with the projection of their major axes perpendicular to each other when one or the other has its major axis parallel to the portion of the ribbon 11 between the cams 49 and 51 and in the bight. The remainder of the apparatus retains its relationship. This embodiment provides for matching the velocity of the ribbon 11 to the printing bight twice per revolution of the earns 49 and 51 at about half the speed of the cams 21 and 23 shown in the embodiment of FIG. 1. Double lobed cams 49 and 51 may be employed where space permits and in accordance with ribbon size. The wider the ribbon, the easier it is to employ multiple lobed cams, since more frictional contact is involved. The advantage derived from employing multiple lobed cams is further economy in mechanical work to drive transfer ribbon 11.

It should be noted that either arrangement allows for the employment of a rewind or reverse capability for the occasion where a multiple impression ribbon is employed.

I claim:

1. In a rotary printing press having an anvil roll against which a printing drum presses to form a printing bight and means for feeding and taking up a transfer ribbon, the improvement comprising:

a rotary shuttle for alternately accelerating and decelerating the velocity of a portion of said ribbon through said bight including,

a pair of like eccentric rollers positioned one on each side of said bight, said ribbon being threaded around at least a portion of the surfaces of said rollers for frictional contact therewith.

2. The rotary ribbon shuttle described in claim 1 wherein said rollers are single lobed cams.

3. The rotary ribbon shuttle described in claim 1 wherein said rollers are double lobed cams.

'4. The rotary ribbon shuttle described in claim 1 wherein said rollers are multiple lobed cams.

5. A rotary printing press utilizing a transfer ribbon comprising;

an anvil roll,

a printing drum pressing against said anvil roll to form a printing bight,

means for feeding and taking-up the transfer ribbon,

and

eccentric rotary means in frictional contact with said ribbon for accelerating and decelerating the velocity of a portion of said ribbon through said bight.

6. The rotary printing press of claim 5 wherein said means for accelerating and decelerating the velocity of a portion of said ribbon includes a pair of single lobe cams, one on each side of said bight, said ribbon being threaded around at least a portion of the surface of each of said cams.

7. The rotary printing press of claim *5 wherein said means for accelerating and decelerating the velocity of a portion of said ribbon includes a pair of double lobe cams, one on each side of said bight, said ribbon being threaded around at least a portion of the surface of each of said cams.

References Cited UNITED STATES PATENTS 1,949,362 2/ 1934 Wickwire 101--244X 2,714,268 8/ 1955 Battey 101-244 2,758,541 8/ 1956 Tison 101-228 3,405,637 10/ 1968 Colwill lO1-244 ERNEST T. WRIGHT, JR., Primary Examiner US. Cl. X.R. 101-228, 33 6 

